You need a visa for Montserrat if you have a Montenegrin passport
Visa options for Montserrat
Electronic visitor visa
Travelers need a visa to visit Montserrat for Business or Tourism. A Montserrat eVisa is the fastest and easiest way of obtaining a visa for Montserrat because travelers can submit their application and supporting documents online. Once the application is approved, travelers receive their eVisa confirmation electronically. A valid visa is required to board the flight. If the visa is expired or doesn’t match the traveler’s passport information, travelers will not be able to board their flight.
This is not offered by sherpa°.
Apply on the government site.